Common metamorphic rocks include phyllite, schist, gneiss, quartzite and marble. Foliated Metamorphic Rocks: Some kinds of metamorphic rocks — granite gneiss and biotite schist are two examples — are strongly banded or foliated.

Granite is an igneous rock, thus option B is correct.

In order to create metamorphic rock, it is vital that the existing rock remain solid and not melt. If there is too much heat or pressure, the rock will melt and become magma. This will result in the formation of an igneous rock, not a metamorphic rock.

Nonfoliated metamorphic rocks are formed around igneous intrusions where the temperatures are high but the pressures are relatively low and equal in all directions (confining pressure).

Nonfoliated rocks contain more coarse grained minerals and generally have a random shape. Because of this, these rocks are very granular in appearance. Examples of nonfoliated rocks are quartzite, marble and anthracite coal.

There are two main types of metamorphic rocks: those that are foliated because they have formed in an environment with either directed pressure or shear stress, and those that are not foliated because they have formed in an environment without directed pressure or relatively near the surface with very little pressure …

Metamorphic rocks are broadly classified as foliated or non-foliated. Non-foliated metamorphic rocks do not have aligned mineral crystals. Non-foliated rocks form when pressure is uniform, or near the surface where pressure is very low. The other minerals have been crushed and deformed into a fine-grained matrix (Mtx).

Common sedimentary rocks include sandstone, limestone, and shale. These rocks often start as sediments carried in rivers and deposited in lakes and oceans. When buried, the sediments lose water and become cemented to form rock. Tuffaceous sandstones contain volcanic ash.

Contact metamorphism is a type of metamorphism where rock minerals and texture are changed, mainly by heat, due to contact with magma. Regional metamorphism is a type of metamorphism where rock minerals and texture are changed by heat and pressure over a wide area or region.

Contact metamorphism is usually restricted to relatively shallow depths (low pressure) in the Earth because it is only at shallow depths where there will be a large contrast in temperature between the intruding magma and the surrounding country rock.

The main difference is that the crystals in an igneous rock is shaped as it crystallized from a melt. The structures in a metamorphic rock are earlier strucures (crystals, sedimentary fragments, etc.) that have been deformed or recrystallized due to heat or pressure, or some chemical change.

Diamond is a metamorphic mineral, as it forms under heat and pressure from solid-state processes. It is found in an igneous rock is brought to the surface of the earth by volcanic eruptions bringing magma to the surface. …

talc

igneous rock

Diamond is the hardest known mineral, Mohs’ 10. Notes: It must be noted that Mohs’ scale is arbitrary and non-linear, i.e. the steps between relative hardness values are not necessarily equal.

boron nitride

(PhysOrg.com) — Currently, diamond is regarded to be the hardest known material in the world. But by considering large compressive pressures under indenters, scientists have calculated that a material called wurtzite boron nitride (w-BN) has a greater indentation strength than diamond.

Surprising Things about Obsidian Surprisingly, the edge of a piece of obsidian is superior to that of a surgeon’s steel scalpel. It is 3 times sharper than diamond and between 500-1000 times sharper than a razor or a surgeon’s steel blade resulting in easier incisions and fewer microscopic ragged tissue cuts.

Cutting edge Obsidian – a type of volcanic glass – can produce cutting edges many times finer than even the best steel scalpels. At 30 angstroms – a unit of measurement equal to one hundred millionth of a centimeter – an obsidian scalpel can rival diamond in the fineness of its edge.

Pound for pound, diamonds are not very good at stopping bullets. The energy absorbed by diamond shattering is much less than the energy absorbed by metals deforming. A plate of steel would be better at stopping bullets than a plate of diamond.

In the absence of oxygen, diamonds can be heated to much higher temperatures. Above the temperatures listed below, diamond crystals transform into graphite. The ultimate melting point of diamond is about 4,027° Celsius (7,280° Fahrenheit).

Diamond is very hard due to the strong covalent bonds and rigid tetrahedral 3d arrangement. It does not conduct electricity, as there are no electrons free to move and carry charge. Carbon atoms have four unpaired electrons and can form four covalent bonds.

Red diamonds

The melting point of Diamond at about 100,000 atm is 4200 K, which is much higher than the temperature of lava. So, it is impossible for lava to melt a diamond. So, if the temperature of lava is above this, the diamond will burn (not melt).